<template>
    <div class="component-upload-image">
        <el-upload
            multiple
            :action="uploadImgUrl"
            list-type="picture-card"
            :on-success="handleUploadSuccess"
            :before-upload="handleBeforeUpload"
            :limit="limit"
            :on-error="handleUploadError"
            :on-exceed="handleExceed"
            ref="imageUpload"
            :on-remove="handleDelete"
            :show-file-list="true"
            :headers="headers"
            :file-list="fileList"
            :on-preview="handlePictureCardPreview"
            :class="{ hide: this.fileList.length >= this.limit }"
        >
            <em class="el-icon-plus"></em>
        </el-upload>

        <!-- 上传提示 -->
        <div class="el-upload__tip" slot="tip" v-if="showTip">
            请上传
            <template v-if="fileSize">
                大小不超过
                <em style="color: #f56c6c">{{ fileSize }}MB</em>
            </template>
            <template v-if="fileType">
                格式为
                <em style="color: #f56c6c">{{ fileType.join('/') }}</em>
            </template>
            的文件
        </div>

        <el-dialog :visible.sync="dialogVisible" title="预览" width="800" append-to-body>
            <img
                :src="dialogImageUrl"
                style="display: block; max-width: 100%; margin: 0 auto"
                alt
            />
        </el-dialog>
    </div>
</template>

<script>
    import { getToken } from '@/utils/auth'
    export default {
        props: {
            value: [String, Object, Array],
            // 图片数量限制
            limit: {
                type: Number,
                default: 5,
            },
            // 大小限制(MB)
            fileSize: {
                type: Number,
                default: 5,
            },
            // 文件类型, 例如['png', 'jpg', 'jpeg']
            fileType: {
                type: Array,
                default: () => ['png', 'jpg', 'jpeg'],
            },
            // 是否显示提示
            isShowTip: {
                type: Boolean,
                default: true,
            },
        },
        data() {
            return {
                number: 0,
                uploadList: [],
                dialogImageUrl: '',
                dialogVisible: false,
                hideUpload: false,
                uploadImgUrl: process.env.VUE_APP_BASE_API + '/file/upload', // 上传的图片服务器地址
                headers: {
                    Authorization: 'Bearer ' + getToken(),
                },
                fileList: [],
            }
        },
        watch: {
            value: {
                handler(val) {
                    if (val) {
                        // 首先将值转为数组
                        const list = Array.isArray(val) ? val : this.value.split(',')
                        // 然后将数组转为对象数组
                        this.fileList = list.map((item) => {
                            if (typeof item === 'string') {
                                item = { name: item, url: item }
                            }
                            return item
                        })
                    } else {
                        this.fileList = []
                        return []
                    }
                },
                deep: true,
                immediate: true,
            },
        },
        computed: {
            // 是否显示提示
            showTip() {
                return this.isShowTip && (this.fileType || this.fileSize)
            },
        },
        methods: {
            // 上传前loading加载
            handleBeforeUpload(file) {
                let isImg = false
                if (this.fileType.length) {
                    let fileExtension = ''
                    if (file.name.lastIndexOf('.') > -1) {
                        fileExtension = file.name.slice(file.name.lastIndexOf('.') + 1)
                    }
                    isImg = this.fileType.some((type) => {
                        if (file.type.indexOf(type) > -1) return true
                        if (fileExtension && fileExtension.indexOf(type) > -1) return true
                        return false
                    })
                } else {
                    isImg = file.type.indexOf('image') > -1
                }

                if (!isImg) {
                    this.$modal.msgError(
                        `文件格式不正确, 请上传${this.fileType.join('/')}图片格式文件!`
                    )
                    return false
                }
                if (this.fileSize) {
                    const isLt = file.size / 1024 / 1024 < this.fileSize
                    if (!isLt) {
                        this.$modal.msgError(`上传头像图片大小不能超过 ${this.fileSize} MB!`)
                        return false
                    }
                }
                this.$modal.loading('正在上传图片，请稍候...')
                this.number++
            },
            // 文件个数超出
            handleExceed() {
                this.$modal.msgError(`上传文件数量不能超过 ${this.limit} 个!`)
            },
            // 上传成功回调
            handleUploadSuccess(res, file) {
                if (res.code === 200) {
                    this.uploadList.push({ name: res.data.url, url: res.data.url })
                    this.uploadedSuccessfully()
                } else {
                    this.number--
                    this.$modal.closeLoading()
                    this.$modal.msgError(res.msg)
                    this.$refs.imageUpload.handleRemove(file)
                    this.uploadedSuccessfully()
                }
            },
            // 删除图片
            handleDelete(file) {
                const findex = this.fileList.map((f) => f.name).indexOf(file.name)
                if (findex > -1) {
                    this.fileList.splice(findex, 1)
                    this.$emit('input', this.listToString(this.fileList))
                }
            },
            // 上传失败
            handleUploadError() {
                this.$modal.msgError('上传图片失败，请重试')
                this.$modal.closeLoading()
            },
            // 上传结束处理
            uploadedSuccessfully() {
                if (this.number > 0 && this.uploadList.length === this.number) {
                    this.fileList = this.fileList.concat(this.uploadList)
                    this.uploadList = []
                    this.number = 0
                    this.$emit('input', this.listToString(this.fileList))
                    this.$modal.closeLoading()
                }
            },
            // 预览
            handlePictureCardPreview(file) {
                this.dialogImageUrl = file.url
                this.dialogVisible = true
            },
            // 对象转成指定字符串分隔
            listToString(list, separator) {
                let strs = ''
                separator = separator || ','
                for (let i in list) {
                    if (list[i].url) {
                        strs += list[i].url.replace(this.baseUrl, '') + separator
                    }
                }
                return strs != '' ? strs.substr(0, strs.length - 1) : ''
            },
        },
    }
</script>
<style scoped lang="scss">
    // .el-upload--picture-card 控制加号部分
    ::v-deep.hide .el-upload--picture-card {
        display: none;
    }
    // 去掉动画效果
    ::v-deep .el-list-enter-active,
    ::v-deep .el-list-leave-active {
        transition: all 0s;
    }

    ::v-deep .el-list-enter,
    .el-list-leave-active {
        opacity: 0;
        transform: translateY(0);
    }
</style>
